The present application relates generally to the field of systems and methods for animal feed production. Specifically, the present application is directed to a system and method for determining starch gelatinization in an animal feed production system.
Animal feeds are created by processing a number of ingredients to create an animal feed product. Feed products may be extruded, expanded, or pelleted by methods well known in the art as described in the 2005 edition of Feed Manufacturing Technology V., Eileen K. Schofield (Technical Editor), American Feed Industry Association, Arlington, Va., and earlier editions. During extrusion, expansion, or pelleting, starch in the feed product is gelatinized which improves digestibility. Additionally, extrusion, expansion, or pelleting improves the storage life of the product by reducing enzyme activity (e.g., lipase activity). Extrusion, expansion, and pelleting processing conditions (e.g., temperature, pressure, and moisture) may be controlled to produce varying levels of starch gelatinization. Starch gelatinization is a process that breaks down the intermolecular bonds of starch molecules in the presence of water and temperature and allows the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This penetration of water increases randomness in the general structure and decreases the number and the size of the crystalline region. The crystalline region does not allow water entry. When heat is applied this region will be diffused, so that the chains start to pull out from each other.
In the pet food industry, a majority of diets are extruded. High temperatures introduced from steam or caused by pressure, “cook” the animal feed product. If the product is not extruded properly, the feed product is susceptible to either overcooking or undercooking. Undercooking the product can result in product that contains starch which will not be fully digested causing the potential for “leaks” of starch into the hindgut including the distal portion of the small intestine, cecum, and large intestine or colon depending upon the animal species. When starch reaches the hindgut, the microbes digest it very rapidly which can contribute to gastrointestinal issues for animals ingesting the feed. Overcooking can cause similar issues, although based on a different mode of action. Overcooking can lead to retrograde starch being formed in the feed product. Retrograde starch is an irreversible insoluble starch formed when the starch molecules are attracted to each other and form bundles of parallel polysaccharide chains by the formation of hydrogen bonds between hydroxyl groups on neighboring molecules. Retrograde starch is not fully digestible by the small intestine of the animals such that the starch reaches the hindgut where it is utilized by microbes as described above.
The degree of cooking has traditionally been measured by sending the finished product to a lab to perform a wet chemistry analysis and measure the level of starch gelatinization. The process usually takes a few days up to a week. During this testing period, the product is usually already being bagged and shipped to distributors. Further, the results generated from traditional measurement may vary widely based on the procedure each individual testing laboratory uses to measure gelatinized starch (i.e., the analysis for the same product may vary depending on which lab analyzed the product).
What is needed is a system and method for rapidly and accurately measuring starch gelatinization in an animal feed product during or contemporaneously with the production of the animal feed product. What is further needed is such a system and method configured to determine whether overcooking or undercooking has occurred such that remedial action may be taken to correct any issues in the production process.